FIG. 1 shows a hair follicle structure 100, which includes a hair follicle 110, hair shaft 120 and one or more associated sebaceous glands 130. A small gap 125 is generally present between the hair shaft 120 and the sides of the follicle 110 in the upper portion of the follicle structure 100 leading to the skin surface 115. One or more sebaceous glands 130 are often connected to this gap via a duct 135, as shown in FIG. 1.
Sebaceous glands 130 secrete an oily substance called sebum 140, which is a mixture of lipids and debris from dead cells shed by the gland 130. The sebum 140 is deposited into the upper portion (infundibulum) of the hair follicle 110, and eventually may rise up to the skin surface 115. Sebum 140 can lubricate and protect hair shafts 120, act as a moisturizer, and can also help to seal the follicle opening 125 from external substances.
Sebum accumulation and/or blockage of the duct 135 between the sebaceous gland 130 and the hair follicle 110 by sebum 140 can be a major cause of the common skin condition acne vulgaris (generally referred to as ‘acne’). Sebum blockages can enlarge to form blackheads or whiteheads. Redness, swelling, and infection may also occur. These acne symptoms can be aesthetically undesirable and socially stigmatizing, and they can also lead to the formation of disfiguring scars.
Present approaches for alleviating acne symptoms and avoiding more serious complications include application of topical solutions of substances such as benzoyl peroxide (available over-the-counter or by prescription) or salicylic acid, or prescription antibiotics such as erythromycin, clindamycin, or tetracycline derivatives. Topical retinoids can also be applied to alleviate acne symptoms. Retinoids include tretinoin (brand name Retin-A), adapalene, and tazarotene and the non-prescription retinol or derivatives. Retinoids appear to influence cells in the follicle lining, which can help to prevent hyperkeratinization of these cells that can lead to blockages.
The effectiveness of such topical treatments, particularly solutions containing retinoids, may generally be limited by the ability of the topical solutions to penetrate deeply into the follicle 110 and into the sebaceous gland 130 itself. Accumulation of sebum 140 and debris in the hair follicle 110 and/or duct 135 leading into the sebaceous gland 130 can inhibit penetration of topical solutions into the follicle region where they may be more efficacious.
Oral intake of isotretinoin, a retinoid (available under the brand names Accutane, Sotret, Clarus, etc.) has been shown to provide long-term reduction of acne symptoms or severity thereof. Isotretinoin can be very effective for treating severe cases of acne. However, oral administration of isotretinoin is believed to cause significant side effects, including liver damage and birth defects when used by pregnant women. For these reasons, treatment of acne using oral administration of isotretinoin generally requires close monitoring and a specified timetable for treatment cycles.
Other techniques that can be used to treat acne with varying degrees of effectiveness include phototherapy (e.g., photodynamic therapy (“PDT”) or treatment with various lasers or intense pulsed light sources). PDT generally involves topical application of a solution containing 5-aminolevulinic acid (ALA) or other photosensitizer precurosors or photosensitizers, followed by irradiation with optical energy to activate the photosensitizer and selectively affect certain tissues where the photosensitizer is present. PDT techniques for treating acne are described, e.g., in U.S. Pat. No. 6,897,238, and various substances that may be used as photosensitizers in PDT procedures are described, e.g., in U.S. Pat. No. 6,034,267.
Follicular keratosis is a common condition that is characterized by excess production of keratin that can block follicles, and produce symptoms such as rashes, swelling, pain and/or ingrown hairs. Although there is no known cure for follicular keratosis, symptoms can be relieved through application of substances such as topical solutions of vitamin A or benzoyl peroxide.
Topical solutions, lotions, etc. are also marketed for application to the scalp to stimulate hair growth, reduce a rate of hair loss, etc. These solutions can contain substances such as minoxidil, azealic acid, and/or dyhydrotestosterone (DHT) blockers. Such solutions may be more effective and/or may be used in lower concentrations if they can be delivered more effectively to the follicle area or certain portions thereof. PDT techniques can also be used to treat hair loss as described, e.g., in U.S. Pat. No. 7,090,691. Better penetration of compounds used in such PDT techniques into the follicle can improve the effectiveness of such techniques.
Thus, in view of the above-described deficiencies, a method and apparatus would be desirable for improved acne treatment and treatment of other skin conditions via more effective application of topical substances into the hair follicle region and optionally into the sebaceous gland. More effective delivery of such substances can allow lower concentrations to be used, can improve efficacy, and can also provide an alternative to more dangerous treatments, such as oral application of isotretinoin.